Process of bleaching and dyeing furs and the like



MOSS new! cute PATENT oFFmE.

HYMAN STEIN, OF ARVERNE, WILLIAM E. AUSTIN, OF NEW YORK, AND IRVING LIEBOWITZ, OF BROOKLYN, NEW YORK, ASSIGNORS TO STEIN FUR DYEING CO., INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROCESS OF BLEACHING AND DYEING FURS AND THE LIKE.

No Drawing. 7

of Bleaching-and Dyeing Furs and the likef of which the following is a specification.

Our present invention relates to methods I of bleaching and thereafter dyeing fibres,

particularly animal fibres, especially fur skins and the like, and aims to devise meth L ods of the general character specified above wherebyarticles of the classes mentioned, especially dark colored fur skins and other fibrous products, particularly of animal ongin, may be bleached or decolorized in a .simple, convenient, economical and expeditious manner, and without impairing the strength or texture of the articles bleached in accordance with the principles of the presentilnv'lention, which articles may, after the bleaching operation, be simply conven iently, economically and expeditlously dyed so as to yield a high grade product characcation in'the bleaching or decolorizing, and subsequentdyeing, of dark colored fur skins which may, by-means' of the method of the present invention, *be bleached or decolorized without impairing the strength or texture of either the leather or the hair of such fur skins, and which may thereafter be dyed the same colors as can at present be applied only to white or very light colored furs, which white or light "colored furs are, as well known to those skilled in the art to whlch theipresent invention relates, comparatively expensive, the combined bleaching or decolorizing and subsequent dyeing operations requiring, under the conditions of thepresent-l-invention only as much. .time, .;1in' the Application filed May 3,

1924. Serial No. 710,829.

average case, as the ordinary fur dyeing process alone.

In the accompanying specification we shall describe an illustrative embodiment of the method of the present invention as applied more particularly to the bleaching or decolorizing and the subsequent dyeing of fur skins or the like. It is, however, to be clearly understood that our invention is not limited to the specific embodiments thereof herein described for purposes ofillustration only,- and that the process may be applied with almost equal success to the bleaching or decolorizing and subsequent dyeing of other fibrous products, particularly of animal ori gin, than the fur skins here specifically described. It may here also be stated that the bleached or decolorized, and the subsequently dyed, products, while described herein as the result of practicing the process herein described and claimed, are themselves described and claimed in another copending application filed by us of even date herewith and entitled Bleached and and the like, Serial No. 710,830. Before describing in detail the aforesaid illustrative embodiment of the method of the present invention, it may be desirable briefly to point out the defects and disad-- vantages of the prior art to which the present invention relates. Hitherto, in attempt ing tobleach or decolorize and thereafter to dye dark colored fur skins and the like, in an effort to convert the same to a light colored search manna dyed furs skin, so that the same might be dyed a light color in the same manner as the natural white or light colored skins might be dyed, it has been customary to use a comparatively powerful bleaching agent in order .to bleach or decolorize the dark colored fur skins or the like. For example,"ithas hitherto been or the like without seriously weakening, or y even destroying, the leather and without weakening or even seriously impairing the natural strength and texture of the hair of such fur skins to such a degree as to render the skins: unfitv for: further use. Furthera. BLtAUHINU a UYtlNli; FLUID MQSS T eibfefltfi TREATMENT & CHEMICAL momrp their fATTQN F TEXTILES & FIBERS,

Imke, such bleaching ordecolorization as principles of thepresent invention will be con (1 be obtained by the use of the bleachfound to be in perfect condition, with their ing agents mentioned above, or their equivastrength, texture and lustre unimpaired. lents, ordinarily required from about 24 to While we do not wish to be limited to 5 about 72 hours for the accomplishment of any particular theory or explanation as to 70 the poor and unsatisfactory results obtainwhy'this remarkable, unexpected and comable by their use. mercially valuable result is obtained, our

By means of the present invention we are present explanation is that the presence in enabled to decolorize or bleach dark colored the fibres of the fur skin or the like of the 1 fur skins or the like without weakening or mineral reducing agent, or its equivalent, 75 destroying the leather of the skins and withlocally prevents too violent action of the out weakening or impairing the natural oxidizing or equivalent bleaching agent, texture and strength of the hair. Skins such as the hydrogen peroxide referred to bleached or decolorized' in accordance with above, but without preventing the bleaching the principles of the present invention may 'or decolorizing action from being carried 80 thereafter be very readily and expeditiousout in the desired manner.- In fact, the ly dyed the same colors, light or otherwise, presence of the protective agent, such as the as can at present be applied with success ferrous compound referred to, or its equivonly to natural white or light colored furs. alent, not only protects the leather'and the 30 Furthermore, the entire combined operation hair of the fur skins or the like from de- 85 of bleaching or dccolorizing the skins and structive or weakening action, but actually thereafter dyeing them in accordance with accelerates the desired decolorizing or the principles of the present invention rebleaching action so that the bleaching opquires only as much, or even less, time as eration takes only from about one (1) to the ordinary fur dyeing process. Furtherabout four (4) hours in place of the 24 more, the resultant bleached or decolorized to 72 hours hitherto required for the im- SkinS and he Subsequently dyed skins are perfect or even destructive bleaching as characterized by the leather of such skins hitherto practiced. coming out of the process in sound condi- Since the protective agent and bleach action as to strength and texture, and by the celerator,-in accordance with the princi les 1 hair likewise coming out of the process in of thepresent invention, generally comprises sound condition as to strength, texture and Y a reducing agent or compound, preferably lustre. In fact, furs treated in accordance of mineral-origin, such as a, ferrous comwith the present invention come out of the pound, for example, f n-. 1 h t hi 1 pr c s after they m d bleaching or dewould tend to be oxidlze more or ess readi- 100 colorizing and'subsequent dyeing operations, ly on exposure to the air, we prefer to add affected less, or onl as much, as furs which to the protective agent, preferably before have been merely yed by the dyeing meththe same is applied to the fur skin or the ods hitherto customarily employed. like, prior to the bleaching of decolorizing ,i

T We have discovered that by treating the operation, a stabilizing agent. The purfur skins or the like which are to be bleached pose of the stabilizing agent is to stabilize or decolorized, prior to the bleaching or dethe protective a ent and to prevent too rapid colorizing step, with a protective agent, genoxidation or deterioration of the same.

erally a reducing compound, preferably of Where, as is preferred, ferrous-sulphate is mineral origin, such as a ferrous compound, used as the protective agent, we prefer tov for example, ferrous sulphate, in some way, use for the .stabil'zin a ent ammonium the reasons for which are at present not w The fur skins or e h e, after clearly understood by us, such protective having been treated with. a solution of the agent, while permitting the bleaching or deprotective compound, I which may or may colorizin action to proceed under the action not contain dissolved therein the stabilizing of the bleaching agent with remarkable agent, are thereafter subjected to the bleachrapidity, protects the leather and the hair ing operation, after which it may be dyed of. the fur skins or the like from any dein any of 'the light or other shades such structive or weakening effect of the bleachas can at'the present time be produced only 55 ing agent. I v. by dyeing natural white or other light 12.

For instance, while decolorization or colored skins. bleaching of the fur skins or the like. The following is a. specific example of one takes place under the action of the bleachmode of'applying themethod of the present ing agent, for example, hydrogen peroxide, invention, it being understood, however,

50 within as short a time as from about'l to that the following description is given about 4 hours, instead of the 24 to 72 hours merelyby way of illustration and that the hitherto required for bleaching fur skins'by process is not limited to the specific details the methods hitherto. in use and'employing' of the following illustrative example: such a bleaching agent, the leather and hair vBrown mouflions are washed .or killed 55 of the skin bleached in accordance with the in an alkaline solution, for example, a solution of sodium carbonate. This Washing operation ordinarily requires from about 2 to about 3 hours. The washed or killed skins are then rinsed and thoroughly hydroextracted. The skins are then immersed in a solution of the protective agent, such as in a solution of ferrous sulphate, and there allowed to remain over night. lVhile the strength of the ferrous sulphate solution or its equivalent may vary within considerable limits, we prefer to use an aqueous solution of ferrous sulphate of a. strength of from about 0.5 to about 5.0 per cent of the solid crystallized ferrous sulphate. by we ght. Such a solution may or may not contain the stabilizing agent. It a stabilizing agent, such as ammonium chloride, is used, we prefer to use it in an amount approximatelyequal to the amount of ferrous sulphate used and equalling from about 0.5 to about 5.0 per cent of ammonium chloride, by weight.

The fur skins or the like, after having been soaked for from about 8 to about 12 hours in the solution of the protective agent, with or without the addition of the stabilizing agent, are then rinsed and hydro-extracted. The treatment apparently impregnates or fills the voids and interstices of the fibres with the solution of protective agent. The fur skins thus treated are now im mersed in a solution of hydrogen peroxide or equivalent bleaching agent. However, in

place of hydrogen peroxide, we may use other bleaching agents, particularly sodium peroxide or sodium perborate, which yield hydrogen peroxide in solution in the presence of certain liberating agents, generally of an acid character. The amount of hydrogen peroxide used may vary from about five (5.0) to about one hundred (100.0) per cent by volume of a three (3.0) per cent solution of hydrogen peroxide. We prefer that the temperature at which the bleaching or decolorizing operation is carried out shall i be between 60 and 100 F.

The skins are subjected to the action of the bleaching or decolorizing agent until they have been sufiic'iently decolorized. The bleached or decolorized skins are then rinsed and can, if desired, be dyed directly in accordance with any of the well known or desirable processes employed for dyeing furs or the like. We may, however, subject the bleached or decolorized skins to the usual dyeing operations of washing and mordanting, and then dyeing the washed and mordanted skins in accordance with the practice hitherto generally employed for dyeing furs.

It may here be stated, especially in connection with the foregoing specific example of applying the method of the present in vention, that the original washing or killing operation to whichthe fur skin or the like is preferably subjected prior to its treatment with the solution of the protective agent, may be combined as a single step with the treatment of the fur skin or the like with the protective agent, as by having the protective agent and also, if desired, the stabilizing agent, present in the alkaline or other solution used for washing or killing the fur skins or the like. Or else, if desired, the washing or killing operation may be altogether omitted and satisfactory results still obtained. It may here also be stated that a metallic salt or salts may be added to the solution of the protective agent. with or without the stabilizing agent, provided such metallic salt or salts are compatible with the ferrous sulphate or equivalent protective agent. In such a case the decolorizing or bleaching process proceeds in exactly the same way as before, while the additional salt or salts act as a mordant for the subsequent dyeing process where a mordant is desired to be employed.

Where the fur is preliminarily washed or killed, as with a solution of an alkaline substance, the nature of the fur will deter mine the nature and strength of the particular alkaline substance, or its equivalent, to be used in the washing or killing oper ation. It may here further be stated that while, in accordance with our experience up to the present time, the foregoing process may be successfully applied to all dark colored furs, the concentration of the reagents employed and the length of time for subjecting the fur skins or the like to the various operations will depend very largely upon the nature of the skins or the like being treated, the factors of temperatures. concentrations, lengths of time of treatment. and the like, for any particular kind of fur, being readily determined by trial and experiment.

The advantages of the foregoing process are numerous and of great practical importance, and may be briefly suimnarized as follows In the first place, the process enables dark colored fur skins or the like to be bleached or decolorized to a white or very light color without destroying or even weakening the leather of the skins, and without impairing the strength, texture or lustre of the hair of such skins. The process is at the same time very simple, convenient, and economical to practice, and while enabling the desired decolorizing or bleaching operation to be conducted safely and with due regard to the strength and texture of the final product, serves in a simple and inexplicable way to accelerate the bleaching or decolorizing operation. a

By means of the present invention we are enabled to accomplish the tremendously important and commercially invaluable result of bleaching or decolorizing the comparatively cheap, dark colored fur skins or the lREAlt-"itlll dl CHEMICAL MODIFL Cress Recreate;

new OF incurs & HBERS, ,2o

like a white or very light color, without destroying or impairing the strength and and thereafter as successfully dyed in all .market.

the light colors hitherto obtainable only by dyeing natural white or light colored skins. The resulting bleached or decolorized, and subsequently dyed, fur skin or the like, which is more fully described and which is claimed in our copending application referred to above, is characterized by. its remarkably fine texture and lustre, and by having practically all of the strength of the unbleached skin. In fact, skins bleached or decolorized, and subsequently dyed, in accordance with the principles of the present invention will be found to have lost less of their strength, texture 'and lustre, than skins subjected merely to the dyeing operation as hitherto practiced. So fine is the product obtained by the practice .of the.

present invention, and so closely does it resemble the skin obtained by dyeing the natural white or light colored fur, that only an expert, if even an expert, can dis- .tinguish the one from the other, while the bleached and light dyed skin fetches almost the same high price that the natural white or light-colored skin fetches in the present It may here be stated that in addition to the mineral protective agent, such asthe ferrous sulphate, with or without the addition of the stabilizing agent, the solution for giving the fur skins or the like their protective treatment for the subsequent bleaching operation may contain other compatible metal salts, as well as suitable protective colloids, such as glue, gelatin, or the like, generally in relatively small amounts.- It may here also be stated that the method described above may be, applied with almost equal success in the treatment of skins which have already been dyed, either a dark or a light color, especially skins which have been unsatisfactorily dyed or spoiled in the dyeing operation, such as skins which have been dyed by the use 'of a mordant consisting of a ferrous compound, such as ferrous sulphate, or an equivalent substance, thus producing from the previously dyed skins the superior product described above.

\Vhat we claim as our invention is:

1. The method of bleaching fur skins and the like, which comprises treating the fibres with an oxidizing agent in the presence of a protecting agent comprising a reducing compound.- I i j v 2. The method of bleaching fur skins and the like, which comprises treating the same with an oxidizing agent in the presence ofan accelerator comprising a mineral reducmg compound.

3. The method of bleaching fur skins and the like, which comprises treating the same with a solution of hydrogen peroxide in the presence of an accelerator comprising a mineral reducing compound.

4. The method of bleaching fur skins and the like, which comprises treating the same with an oxidizing agent in the presence of an accelerator comprising a ferrous compound.

5. The method of bleaching fur skins and the like, which comprises treating the same with a solution of hydrogen peroxide in the presence of an accelerator comprising a ferrous compound.

6. The method of bleaching fur skins and the like, which comprises treating the same with a solution of a protecting agent to which has been added a stabilizing-agent,

and thereafter subjecting the articles so treated to the action of a bleaching agent.

7. The method of bleaching fur skins and the like, which comprises treating the same with a solution of a protecting agent to which has been added a stabilizing agent, and thereafter subjecting the articles so treated to the action of a solution of hydrogen peroxide.

dearth Rent 8. The method of bleaching fur skins and the like, which comprises treating the same with a solution of a mineral reducing agent to which has been added a stabilizing agent, and thereafter subjecting the articles so treated to the action of a bleaching agent. 9. The method of bleaching fur skins and the like, whichcomprises treating the same with a .solution of a ferrous compound to which has been added a stabilizing agent, and thereafter subjecting the articles so treated to the action of a bleaching agent.

10. The method of bleaching fur skins and -to which has been added ammonium chloride, and thereafter subjecting the articles.

so treated to the action of a solution of hydrogen peroxide.

, thelike, which comprises treating the same 12. The method of bleaching fur skins.

and the like, which comprises treating the same with a solution of a ferrous compound to which has been added ammonium chloride, and thereafter subjecting the article so treated to the action of a bleaching agent;

13. The methodof bleaching fur skins and the like, which comprises treating the same with a solution of a mineral reducing agent to which has been added ammonium chloride, and thereaftersubjecting the artieles so treated to the action of a bleaching agent.

same with a solution of a protecting agent g to which has been added ammonium chloride, and thereafter subjecting the articles so treated to the action of a bleaching agent.

15. The method of dyeing animal fibres, particularly fur skins and the like, which comprises bleaching the same in the presence of a fibre-protecting bleach accelerator comprising a ferrous compound, and thereafter dyeing the product so bleached.

16. The method of dyeing animal fibres, particularly fur skins and the like, which comprises bleaching the same with a solution of hydrogen peroxide in the presence of a fibre-protecting bleach accelerator comprising ferrous sulphate, and thereafter dyeing the product so bleached.

17. The method of dyeing animal fibres, particularly fur skins and the like, which comprises bleaching the same in the presence of a fibre-protecting bleach accelerator comprising a ferrous compound to which has been added a stabilizing agent, and thereafter dyeing the product so bleached.

18. The method of dyeing animal fibres, particularly fur skins and the like, which comprises bleaching the same with a solution of hydrogen peroxide in the presence of a fibre-protecting bleach accelerator comprising ferrous sulphate to which has been added ammonium'chloride, and thereafter dyeing the product so bleached.

19. The method of dyeing animal fibres,

particularly fur skins and the like, which comprises bleaching such fibres .in the presence of a fibre-protecting agent comprising a reducing substance, and thereafter dyeing the bleached product.

20. The method of dyeing animal fibres, particularly fur skins and the like, which comprises bleaching such fibres in the presence of a fibre-protecting agent comprising a ferrous compound, and thereafter dyeing the bleached product.

21. The method of dyeing animal fibres, particularly fur skins and the like, which comprises bleaching such fibres in the presence of a fibre-protecting agent comprising ferrous sulphate, and thereafter dyeing the bleached product.

22. The method of dyeing animal fibres, particularly fur skins and the like, which comprises bleaching such fibres with a solution of hydrogen peroxide in the presence of a fibre-protecting agent comprising a reducing substance, and'thereafter dyeing the bleached product.

23. The method of dyeing animal fibres, particularly fur skins and the like, which comprises bleaching such fibres with a solution of hydrogen peroxide in the presence of a. fibre-protectin agent comprising a ferrous compound, and thereafter dyeing the bleached product. L

2-1. The method of dyeing animal fibres,

particularly fur skins and the like, which comprisesbleaching such fibres with asolution of hydrogen proXide in the presence of a fibre-protecting agent comprising ferrous sulphate, and thereafter dyeing the bleached product.

In testimony whereof, we have signed our names to this specification this 23rd day of April,1924.

HYMAN STEIN. WILLIAM E. AUSTIN. IRVING LIEBOWITZ. 

